It is the long-range objective of this project to study various biological systems which are either actually involved in the visual process or which may serve as models for such systems which are relevant to the transparency or opacity of ophthalmic tissues. Of current interest are the structure and cross-linking mechanisms of fibrinogen and the physical, chemical, and biological properties of the smooth muscle protein filamin. BIBLIOGRAPHIC REFERENCE: Shizuta, Y., Shizuta, H., Gallo, M., Davies, P., Pasten, I., and Lewis, M.S.: Purification and properties of filamin, an actin binding protein from chicken gizzard. J. Biol. Chem. 251: 6562-6567, 1976.